Processes for improving tobacco quality and varying tobacco flavour are constantly being sought. With these overall goals in mind, efforts are currently spent on i.a. the removal of proteins and phenolic compounds such as polyphenols from tobacco, see e.g. U.S. Pat. No. 5,601,097, which relates to a method for reducing protein and polyphenol content of a tobacco material.
It has been reported that of the polyphenols present in tobacco leaves chlorogenic acid is predominant and that low levels of chlorogenic acid in tobacco leaves leads to low levels of the undesired component catechol in tobacco smoke, Schlotzhauer W.S. (1992), Journal of Analytical and Applied Pyrolysis. Vol 22, page 231-238.
A process for removing phenolic compounds from tobacco which makes use of solid adsorbents such as alumina, is disclosed in U.S. Pat. No. 3,561,451. U.S. Pat. No. 5,601,097 discloses the use of another insoluble adsorbent, viz. polyvinylpolypyrrolidone (PVPP), in such process. However, these methods are disadvantageous in being relatively non-selective.
GB 2069814 relates to a method of changing the structure of tobacco, changing its chemical composition and improving its sensorial feature by submitting tobacco to the action of enzymes selected from oxidoreductases (e.g. monophenol monooxygenase, EC 1.14.18.1), lyases, hydrolases and microorganisms constituting a source of such enzymes.